void calculateLighting(float3 normal, float3 lightVec, float3 viewVec, float specPower,
	out float3 diffuseTerm, out float3 specTerm)
{
	diffuseTerm = saturate(dot(normal, lightVec));
  
	float3 refl = reflect(normalize(-lightVec), normal);
	specTerm = pow(saturate(dot(refl, viewVec)), specPower);
}